INSTALLATION GUIDE  issue 2000       Back to Keystone Price List

The Superfit interlock utilizes the inherent spring tension in the metal. Ideally, the top section should be as resilient as the bottom shank. However the degree of resiliency is relative to ring size. For example, a 2 1/2 mm shank in size 8 would safely join with a rigid top section, but would not be safe enough as a wedding band.  For a wedding band in size over 5 1/2 we recommend a 4mm shank.  

Before installation, check the resilience of the customer's ring. Cutting if open at the bottom will allow you to press inwardly and determine whether to install it directly as shown in Fig#1 or over a cut-out bridge of under-bezel as shown in Fig #2, A & B. Make sure the customer's ring is shaped to the required size. In case of invisible settings or difficulty in changing the given structure, the round shape can be achieved with a creative fit of the under-bezel. In order to demonstrate how it should be done, we offer a 40% labor discount on the first installation only.  

SOLDERING
The hinge pins are not soldered; they are riveted except for tapered shanks. Before installation, clean the old ring to prevent any dirt from permanently adhering to stones. Protect stones that can be affected by heat. WHERE TO CUT: place the ring and the Superfit shank over mandrel to determine the cutting lines on both rings. For soldering, several methods can be used. They include: binding wire, locking in head shank tweezers or just holding the bottom shank in self-locking tweezers. Coat with boric acid and flux the joints. Start soldering at the hinged area. This will allow adjustment before soldering the latched area. When soldering near the latch or hinged area, apply a SOLDER STOP SOLUTION to prevent an "overflow" problem. After soldering, quench in MINERAL OIL to restore the inherent spring tension. Wipe off, pickle and clean. We have now added LASER TECHNOLOGY which enables us to fuse gold or platinum in close proximity to diamonds and emeralds.

ADJUST SPRING TENSION

To test the spring tension, pull apart and release.  If spring back is sluggish, INCREASE tension by spreading the bottom shank as shown. If it is too hard to close, DECREASE in small increments as shown in Fig. #3.

FINISHING
When removing metal, preserve the latch surface and tongue thickness. The inside and outside edge of a 2 1/2mm shank can be rounded slightly. The 4mm shank has more metal for dome or comfort finish. A dome finish may expose the latch pin. Solder the exposed latch pin with care to prevent an "overflow". Before polishing, increase spring tension to protect separation lines. Check if tongue is flush with inside radius. Check if latch is firmly in place and its tail-end is flush with the surface. DO NOT USE a soft buffering wheel as it may distort the separation lines and the solid look. After polishing, open the ring for ultrasonic cleaning., Finally, before closing, apply a touch of grease on extension balls, tongue-end and hinge area.

THE INTERLOCK

Figure 4 shows a partially open position that is poised for a spring back to a closed position. Unless the "latch tail" comes in contact with the "shoulder" the ring will not open. This demonstrates the built-in safety against accidental opening. The added safety is provided by its audible closing snap.

WEAR AND TEAR
The kind activity that will bend a regular ring out of shape will also bend a Superfit and silence its audible snap. The absence of an audible snap is an urgent signal to adjust the spring tension. Because a sluggish contact will cause premature wear of the interlock. For restoring spring tension, see Fig. #3.

TAPERED SHANKS
These shanks are tapered from top to bottom or side to bottom. Tapered shanks are also helpful in lessening the rigidity that comes from wider shanks in small ring sizes. The tapering will expose hinge and latch pins. Solder the pins carefully. Do not taper a 2 1/2mm shank.

60/40 SPLIT SHANKS
These shanks are special orders. For example, size 7.0 in 60/40 combines an 8 1/2 top with a 5 1/2 bottom. Both are shaped to size 7.0 before assembly. A 60/40 shank is limited to downsizing.

WAX APPLICATIONS
Because your wax model will adhere to our Superfit plastic components, it is possible to incorporate a Superfit option into any ring line at a nominal price difference. For single custom jobs allow 14 days turnaround.

WEDDING BANDS
Given their daily exposure to wear and tear, we now have available 4mm #90 in 2 1/4mm thickness and 6mm #100 in 2 1/2mm thickness. The added improvements are bound to please you and expand the market for dome and channel set wedding bands with a Superfit option.

SEMI-FINISH SOLITAIRE

OUT-OF-WARRANTY SERVICE
If a ring has been improperly installed, sized, repaired, or deformed and has caused the interlock to wear out beyond repair, we will allow a 50% credit for the shank and allow a 40% discount on our installation.
Customers should be provided with a Superfit inspection after 3 months to check for wear.  They should be made aware of their responsibility to listen to the audible closing snap.

SIZE-TAKING
Size-taking can be a unique sales opportunity. Size-taking with a Superfit demo sample allows everyone to discover the real difference between finger and knuckle size. There is no substitute for size-taking with a Superfit ring in the right size. Given the importance of size-taking and its impact on a spur-of-the-moment sale, special terms for a set of 12 demo samples are available.